In medicine, a need frequently arises to cut and remove small volumes of tissue from the body as a treatment or for diagnosis purposes. This may be essential for example during acquiring tissue for a biopsy, removing calcification from inner walls of obstructed blood vessels or creating paths for drainage of excessive liquids such as in Glaucoma condition.
Tools are available for cutting soft as well as hard tissues in the body. One example is presented in U.S. Pat. No. 6,361,504 which provides a hollow tubular shaped biopsy needle having a hollow elliptical cross section shaped lumen therethrough, and the method for fabricating the needle and the apparatus for operating the needle.
In addition, U.S. Pat. No. 7,344,546 describes a device for intralumenal removal of tissue from inside blood vessels using an advanceable and rotatable cutter assembly designed for differential cutting. One embodiment of the cutter assembly includes a cutter with blades that are designed and arranged to form an acute blade angle of attack with the matter-to-be-removed. The cutter assembly is axially advanceable by translating the drive shaft and rotatable by rotating the drive shaft. The occlusive material is scraped by the cutter assembly and may be aspirated to remove the material from the body cavity. The cutter assembly may provide aspiration ports positioned between facing surfaces of the blades.
Further, U.S. Pat. No. 4,887,613 discloses a cutter that penetrates at its forward end into, and excises, obstructive tissue in a lumen in a living being by providing two spaced external segments of a conical generally hollow portion with cutting surfaces at their edges. The cutter may have a forward portion of restricted dimensions to facilitate the penetration of the cutter into the obstructive tissue. A progressively expanding portion such as a truncated cone extends rearwardly from the portion of restricted dimensions. In this way, the cutter expands the area of excision of the obstructive tissue from the lumen wall at progressive positions rearwardly from the forward end. The obstructive tissue in the lumen at the progressively expanding positions may be excised at the positions of penetration of the obstructive tissue by rotating the cutter manually or by a motor. The cutter may also have a hollow portion of substantially constant dimensions, such as a hollow cylinder, at the laterally expanded end.